Ahnenerbe

Ok, so I have the speed bug. I have a 89 L98 and have done small mods to a very stock 350, 1.6 rockers, 24lb injectors, hotter ignition, and true dual exhaust. What I want to accomplish is a choppy noticeable idle with a decent HP boost. I really don't want to change the springs unless I have to, they are crane springs good to a 480 lift (IIRC) and have 30k on them. , and without retuning computer. I want the ecm to get along with cam choice. I see lots of recommendations on the web, but nothing answers all questions.

On a side note, I know the L98 has roller lifters. If someone wanted to go cheap, could they install a reg flat tappet cam/lifters in this motor without any mods?
Thanks for the advice!!

84 4+3

What year is the car? Some l98s have flat tappet. As for cam choice, look for something a little milder than a cc503. No matter what you should get a chip burned. Engine will only benefit. Maybe something like an lt4 hot cam.

slow-vette

Op stated that he has an 89 in his original post which has roller lifters. Even if you can convert back to flat tappet the losses would not make the cost savings worth it. Roller gives more stable valve train, less friction and wear, and better valve control. Not worth it to get rid of rollers.

84 4+3

missed the 89 part.

If I had a roller I'd use it. The cam itself isn't much more tbh. Rollers and the likes can be reused too so...

Ahnenerbe

I figured it would be bad to revert, but wanted to ask ntl. SO what would be the best cam for a choppy idle without tuning?

vader86

I don't think youre going to find what you want within your constraints. To get the choppy idle you'll need the right amount of overlap/LSA, but without tuning you could end up dying at a stoplight. Those cams will have more duration and likely more lift than your springs warrant. Even the ZZ9, though it can have a slight chop, wants more lift than .480. The extra duration will be wasted with the TPI intake on there as it is now so you'll be choking the **** out of it. Its worth it to you to throw this money and labor on the install away?

sstonebreaker

I would probably go with a Crane 104224. The thing is those TPI intake manifolds are done around 4500 rpm, so getting a super high revving cam will kill performance until you add a Lingenfelter or TPIS intake. Crane street/strip cams are ground with 5 degrees of advance, which makes them better for torque in the midrange but not so much for high rpm horsepower.... which is exactly where the TPI engine shines.

I used this cam for years in my 96 impala ss and loved it. Car made 320 rear wheel hp and 400 rear wheel torque. It weighed 4400 with me in the car, about a thousand pounds more than a C4 vette, and it still ran low 13's at 106 mph. You shouldn't have any problem getting into the low 13's/high 12's even with the stock intake manifold.

tequilaboy

I would consider something like this to work within your constraints (40 degrees overlap):

http://www.compcams.com/Company/CC/c...?csid=198&sb=2

or this one (50 degrees overlap):

http://www.compcams.com/Company/CC/c...?csid=199&sb=2

want even more? (60 degrees overlap):

http://www.compcams.com/Company/CC/c...?csid=200&sb=2

Ahnenerbe

What about the idle? From what others are saying I may be too unrealistic if I want the choppy idle with no mods. I could install better springs and perhaps look into a tune, I am really wanting that nasty sounding idle at the stoplight.

JasBass

I agree with the other posters. The stock TPI really is the problem if you want to get into cams. My 89 6 speed had a LT4 hot cam installed by the PO, but they did nothing for increased airflow. It definitely lost a little lower end torque and is completely done at 4500-4750 (as compared to other L98s i've driven). LT4 isn't a bad choice, nice idle like you want, and there is lots of support for this cam; but LT4 cam needs the better flowing intake. I plan on going to the miniram at some point

sstonebreaker

The Crane 104227 cam has a moderately choppy idle. If you install a radical exhaust, you will hear the chop. Not race car choppy, it's more subtle than that, but a fellow gearhead will know something's there, especially if you keep the idle around 500 rpm. If you want a cam with a really nasty car-shaking idle (and I know how you feel - my C5 has a cam that shakes the car at stoplights), you need to seriously think about upgrading your intake. That L98 intake was intended for pickups. If a Lingenfelter or TPS intake is too expensive, another intake that would be excellent for your car is the Edelbrock Performer RPM. It's a carb intake so you'e need a new throttle body, but it will extend your rpm range to 6000 rpm without much torque loss. And you could go with an even bigger cam for that choppy idle without losing anything.

And if you want a super choppy idle while keeping the TPI intake, try this:

Ahnenerbe

Thanks for all the answers, this is what makes this forum awesome. Took the car out last weekend for the Goodguys car show and after seeing some the BA cars and thumpin idles, I really want to do something to this car. It sucks that the intake is so restrictive, I could try to hog it out and put on a bigger TB, but my goal is to go cheap without spending a lot of money. I was hoping to just stab in a better cam and call it a day. The Crane cam seems to be a good choice, but the Thumper series is really what I am looking for. Sounds like with that type I need a full top end redo, plus a tune.

cv67

Thumper cams not a good choice, please dont choose by sound. Lope does not equal power.

sstonebreaker

You're better off saving up and doing all your mods at once.

clove86

Will this work on stock L98?


Note will not work on stock roller cam?


Wrong thread! Sorry

rpoL98

Cloyes 1145
Cloyes 3017

clove86

Thank you.
That's exactly what I was looking for

MDstar2

I have an 89 with the Lingenfelter 211/219 cam in it. I'm using the stock intake that has been slightly ported with Edelbrock Corvette heads. The car runs high 12's and sounds really nice. Lingenfelter recommended a 2600-2800 stall converter and I chose a 2400. It's a little tight for me. Here's a sound clip of it.

sstonebreaker

That's about how the 104227 sounds like. It's got about 5 degrees more duration on the exhaust though. I believe the Lingenfelter cam has slightly more lift.

MDstar2

With 1.6 rockers I believe the lift is .562 on intake and exhaust.